Dithering is something that you need the most when you are working with either a very limited or a fixed color palette. On the NES backgrounds were dithered because you had so few colors to work with per tile. EGA era PC games used dithering because the standard 16 color choices weren't very useful. Modern pixel artist don't have these technical limitations to work with. And I think that for most, dithering just doesn't look very appealing vs adding an intermediate color.
Anti-aliasing is on the other side of technology window, from an era where there was enough resolution and color choices to support those techniques, but before 3d really took over. By the time you have that level of rendering capability, your are starting to push into the realm of photo-realistic or cartoon techniques. Late in the Super NES and VGA era the trend was away from hand drawn pixel art, and towards high resolution renders scaled down. And when you're working in that space today, you're starting to lose the appeal that the limitations of pixel art offer.
This is all conjecture though. And I'm sure there are pixel artists out there doing amazing things with dithering and anti-aliasing.